--example #1
set condition value before loop
do{
    // do some work
    // update condition value
}while(condition);

-- example #2
int counter = 5;
int factorial = 1;
do {
  factorial *= counter--; /* Multiply, then decrement. */
} while (counter > 0);
System.out.println(factorial);


http://en.wikipedia.org/wiki/Do_while_loop#Java